Use of flame tree flower extract for the preparation of a preparation for preventing and treating sheath blight

Abstract

The application provides use of a flame tree flower extract for preparing a plant disease fungus inhibiting preparation, which can be used for targeted prevention and control of rhizoctonia solani, can effectively prevent and control sheath blight and apple tree rot disease, guarantees the quality of agricultural products, can avoid the disadvantages of chemical agents, meets the development needs of green agriculture and ecological protection, and has important practical application value.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceuticals, specifically relating to the use of flame tree flower extract in the preparation of agents for the prevention and treatment of sheath blight. Background Technology

[0002] Fungal diseases, as one of the most significant crop disasters, seriously threaten global food security and the sustainable development of modern agriculture. For a long time, agricultural production has relied excessively on chemical pesticides for disease control; however, this overuse has led to a series of severe challenges. Statistics show that due to the long-term, singular use of chemical pesticides, a population including more than 40 major crop pathogens has developed significant resistance, resulting in a sharp decline in control effectiveness. At the same time, the harmful components in chemical pesticides are difficult to degrade in nature, causing not only ecological degradation and a sharp decline in biodiversity, but also posing a potential threat to human and animal health through bioaccumulation in the food chain. This runs seriously against the requirements of today's green agricultural development and ecological civilization construction.

[0003] Sheath blight, a globally prevalent and highly contagious soil-borne fungal disease, poses a serious threat to the yield and quality of the world's three major food crops (rice, wheat, and maize). In rice production, sheath blight is listed as one of the three major diseases, with a wide range of incidence and high frequency, severely hindering normal plant growth and nutrient absorption. Affected by changes in planting methods and excessive nitrogen fertilizer application, the disease has worsened in recent years, typically leading to a 10%–30% reduction in rice yield, and in severe cases, losses can exceed 50%. In wheat, this disease (also known as pointed eye disease) is mainly caused by Rhizoctonia graminearum and can infect wheat throughout its entire growth cycle. Infection in seedlings can lead to browning and even death and rotting of the coleoptile; infection in mature plants results in oval-shaped eye spots at the base of the stem, leading to plant necrosis, lodging, and the production of withered and whiteheaded ears. Sheath blight not only causes huge yield losses (e.g., China once lost approximately 530,000 tons of wheat annually) but also significantly reduces the quality of wheat grains. In maize production, sheath blight also exhibits extremely destructive power. This disease primarily infects the leaf sheaths and ears, forming typical cloud-like lesions that lead to leaf sheath rot and stalk lodging. In most maize-producing areas of my country, the incidence of sheath blight is often above 40%, and in some regions even as high as 95% to 100%. After infection, yields are generally reduced by more than 10%, and in severe cases, it can even lead to total crop failure.

[0004] Studies have shown that the main microorganism causing these diseases is *Rhizoctonia solani* Kühn. In summary, due to global warming, the widespread use of straw return to the field, continuous cropping, and excessive nitrogen fertilizer application, the pathogen causing rice sheath blight is accumulating in the soil, and its damage is increasing year by year. Chemical control mainly relies on jinggangmycin and thifluzamide. Although these are simple and fast-acting, long-term, high-dose application of a single drug leads to increasingly poor control efficacy with increasing dosage, and also causes increasingly serious environmental pollution, making control more difficult. Therefore, new methods are urgently needed to control rice sheath blight. Against this backdrop, the development of highly efficient, safe, and environmentally friendly alternative pesticides is particularly urgent. Therefore, in-depth research on the extraction of active ingredients from plant-derived pesticides and their antibacterial mechanisms is not only key to overcoming the limitations of traditional chemical pesticides, but also crucial technical support for achieving the green transformation of agricultural production and ensuring the quality and safety of agricultural products.

[0005] Therefore, there is an urgent need to develop efficient, stable, and targeted plant-derived fungicides for the control of sheath blight. Summary of the Invention

[0006] This invention provides a highly efficient and stable plant-derived fungicide that can specifically inhibit Rhizoctonia solani, effectively preventing and controlling sheath blight and ensuring the quality of agricultural products, while avoiding the drawbacks of chemical agents. It meets the needs of green agriculture and ecological protection development and has important practical application value.

[0007] This invention provides the use of flame tree flower extract in the preparation of agents to prevent and control sheath blight.

[0008] Furthermore, the above-mentioned flame tree flower extract is a water extract or an alcohol extract.

[0009] The aqueous extracts of this invention can be obtained using hot water extraction, cold water soaking, distillation extraction, etc.; the alcoholic extracts of this invention can be obtained using hot alcoholic extraction, cold alcoholic soaking, reflux extraction, etc. Furthermore, the pathogen causing the aforementioned sheath blight is Rhizoctonia solani.

[0010] Furthermore, the above-mentioned formulations also include pharmaceutically acceptable excipients.

[0011] Furthermore, when the above-mentioned flame tree flower extract is used to prepare agents for the prevention and control of sheath blight, the concentration is 0.3-6 mg / mL.

[0012] This invention uses extracts from the flowers of the flame tree to conduct antibacterial experiments on Rhizoctonia solani, Cordyceps militaris, Colletotrichum gloeosporioides, Botrytis cinerea, Fusarium oxysporum (bitter melon type), and Pyrethrum indica. The results showed that it has a good inhibitory effect on the plant disease Rhizoctonia solani, providing a new plant-based formulation for the prevention and control of sheath blight. Attached Figure Description

[0013] Figure 1 The image shows the inhibitory effect of the extract on the specific form of Fusarium oxysporum in bitter melon. Figure 2 The toxicity curve of the extract against the growth inhibition of Fusarium oxysporum specific type; Figure 3 The image shows the inhibitory effect of the extract on Botrytis cinerea. Figure 4 The toxicity curve of the extract against the growth inhibition of Botrytis cinerea is shown. Figure 5 The image shows the inhibitory effect of the extract on Colloidal anthracnose. Figure 6 The toxicity curve of the extract against the growth inhibition of Colloidal anthracnose is shown. Figure 7 The image shows the inhibitory effect of the extract on black rot scabies. Figure 8 The toxicity curve of the extract against the growth inhibition of *Heterotrophus purpureus* is shown. Figure 9 The image shows the inhibitory effect of the extract on Rhizoctonia solani. Figure 10 The toxicity curve of the extract against the growth inhibition of Rhizoctonia solani is shown. Figure 11 The image shows the inhibitory effect of the extract on *Pyrrosia lingua*. Figure 12 The toxicity curve of the extract against the growth inhibition of *Pyrrosia lingua* is shown. Figure 13 The graph shows the inhibitory effect of the extract on different pathogens at different concentrations. Detailed Implementation

[0014] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to examples. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained in the art without creative effort should fall within the scope of protection of the present invention.

[0015] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. Example 1: Preparation method of Flame Tree Flower Extract

[0016] Step S1: Take fresh flower samples of the flame tree (Spathodea campanulata) and dry them rapidly in an oven (stacked forced-air drying oven, model DHG-9120L-3) at 28℃. Step S2: Crush the material from S1 in a pulverizer (Fang Gongzi FGZ-2500C - knob); Step S3: Mix the powder obtained in S2 with 75% ethanol at a ratio of 1:3 and perform ultrasonic extraction at 30 °C for 30 min. After filtration, soak the powder again and repeat the above steps three times. Finally, combine the filtrates.

[0017] Step S4: Pour the filtrate from S3 into a vacuum distillation concentrator IKA (Shanghai Yarong Biochemical Instrument Factory) and concentrate it at 45℃ to 100 mg / mL. This concentrate will be used as the raw material for the Flame Tree Flower Extract. Example 2 Antibacterial effect experiment

[0018] 2.1 Experimental Procedure Step S1: Prepare potato glucose agar (PDA) medium. Weigh 200.0 g peeled potato pieces, 20.0 g glucose, and 15 g agar, and add deionized water to 1000 mL. Sterilize by steaming at 121 ℃ and 0.1 MPa for 20 min.

[0019] Step S2: Activation of the test bacteria (source: provided by the Key Laboratory of Plant Pathology, College of Plant Protection, Shanxi Agricultural University and the College of Breeding, Hainan University). In a clean bench (Shanghai Boxun Medical Bio-Instrument Co., Ltd.), the melted PDA medium was poured into a petri dish near the flame of an alcohol lamp. The inoculation needle and punch were repeatedly heated in the outer flame of the alcohol lamp. After cooling, holes were punched along the edge of the colony using the punch, and the inoculated bacterial cake was placed in the center of the solidified PDA medium using the inoculation needle. The dish was then sealed and incubated in a constant temperature incubator at 25°C for 7 days.

[0020] Step S3: Preparation of drug-containing plates: The original drug obtained in Example 1 was added to a sterilized PDA culture medium at 45°C. The drug and culture medium were mixed to prepare drug-containing plates with concentrations of 5 mg / mL, 2.5 mg / mL, 1.25 mg / mL, 0.625 mg / mL, and 0.3125 mg / mL. A culture medium with an equal volume of sterile water was used as a blank control. Each treatment was repeated 3 times.

[0021] Step S4: Using a 0.7 cm punch, collect mycelial discs from the activated target strain culture medium (for Rhizoctonia solani, directly inoculate one sclerotium, with a sclerotium diameter of 0.15 cm). Use an inoculation needle to pick up the mycelial discs and inoculate them into the center of the drug-containing plate in S7. Seal the drug-containing plate with the inoculated bacteria and place it in an inverted incubator at 25 ℃ for 5-7 days. When the colonies in the blank control have grown to more than two-thirds of the volume of the culture dish, measure the colony diameter.

[0022] Step S5: Data Processing. When the colonies in the blank control reached approximately two-thirds of the volume of the petri dish, the colony diameter was measured using the cross-sectional method, and photographs were taken to record the effect of the drug-containing plates on the fungal colony morphology. The inhibition rate was calculated using Excel software, and virulence analysis was performed using IBM SPSS Statistics 26.

[0023] (Other fungi) Mycelial growth inhibition rate (100%) ×100%; (Rhizoctonia solani) Mycelial growth inhibition rate (100%) ×100%; 2.2 Experimental Results As shown in Table 1 below, the toxicity test of the extract of *Rhizoctonia solani* against the tested pathogens shows that the inhibitory effect of the extract on the tested pathogens, from high to low, is as follows: *Rhizoctonia solani* > *Desmodium styracifolium* > *Colletotrichum gloeosporioides* > *Botrytis cinerea* > *Fusarium oxysporum* (bitter molluscum) > *Pyrrosia lingua*, with corresponding EC50 values ​​of 0.001 mg / mL, 2.677 mg / mL, 4.75 mg / mL, 10.936 mg / mL, 13.998 mg / mL, and -- mg / mL, respectively; From Table 2 and... Figures 1-12 (a~f represent CK, 5 mg / mL, 2.5 mg / mL, 1.25 mg / mL, 0.625 mg / mL, and 0.3125 mg / mL, respectively.) The figure shows that the extract of *Rhizoctonia solani* showed the best antibacterial effect against *Rhizoctonia solani*, the pathogen of sheath blight, at concentrations of 0.3125 mg / mL to 5 mg / mL, with all concentrations exceeding 95%. For other fungi, the antibacterial effect was better at higher concentrations. At a concentration of 5 mg / mL, the inhibition rate against *Hemiberlesia oleracea*, the pathogen of apple tree canker, was 60.17%. The inhibition rates against *Colletotrichum gloeosporioides*, the pathogen of tomato gray mold, *Fusarium oxysporum*, the pathogen of bitter gourd wilt, and *Pyrrosia lingua*, the pathogen of rice blast, were lower, reaching 50.00%, 29.46%, 24.86%, and 3.26%, respectively.

[0024] Table 1. Virulence determination of Flame Tree Flower Extract against Tested Pathogens

[0025] Table 2. Inhibitory effects of Flame Tree Extract on Six Plant Pathogens

Claims

1. Use of Flame Tree Flower Extract in the Preparation of Agents for the Prevention and Control of Sheath Blight.

2. The use as described in claim 1, characterized in that: The flame tree flower extract is a water extract or an alcohol extract.

3. The use as described in claim 1, characterized in that: The pathogen causing the sheath blight is Rhizoctonia solani.

4. The use as described in claim 1, characterized in that: The formulation also includes pharmaceutically acceptable excipients.

5. The use as described in claim 1, characterized in that: When the flame tree flower extract is used to prepare agents for the prevention and control of sheath blight, the concentration is 0.3-6 mg / mL.

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